Haflong: Three policemen were injured, one of them critically, when unidentified persons hurled a grenade at them during patrol duty in Assam's Dima Hasao district in the wee hours today, a police officer said.

The grenade was hurled at the policemen at 2 am while they were on duty in Ram Nagar under Haflong police station here injuring three of them, the officer said, adding, the condition of one of them was said to be critical.

The injured have been identified as Dharmendra Das, Tilak Nath and R K Rajesh Singh, whose condition, doctors said was critical. They have been admitted to Haflong Civil Hospital.

Investigations are on and a search has been launched to nab the miscreants, the officer added.